Multistation communication system



Oct. 28, 1941. F. G. HALLDEN MULTISTATION COMMUNICATION SYSTEM FiledFeb. 24, 1940 2 Sheets- Sheet l INVENTOR. fiEDEH/C/f 6. HALLDE/V fiwATTORNE I IF I I I A I Um I I I L Oct. 28, 1941. F. G. HALLDENMULTISTATION COMMUNICATION SYSTEM Filed Feb. 24, 1940 2 Sheets-Sheet 2NGE A TTURNE Y.

Patented Oct. 28, 1941 MULTISTATION COMMUNICATION SYSTEM Frederick G.Hallden. Bellerose, N. Y., assignor to Postal Telegrap New York, N.

h-Cable Company (New York), p Y., a corporation of New York ApplicationFebruary 24, 194o, seria1 No. 3,20 ,554

9 Claims. (Cl. 178-2) This invention relates to printing telegraphcircuits and more particularly to printing telegraph circuits utilizinga single line conductor to interconnect a multiplicity of printingtelegraph instruments.

' In printingtelegraph systems it is often desired to have a pluralityof way-stations'which may be selectively interconnected with a printerset at a main ofii'ce for communication. It is desirable that suchsystems be made as simple as possible and that a simplified selectivearrangement be provided" atthe main office for selecting any desiredone'of the way-stations for communication. It is also desirable that insuch systems the operators'at any of the way-stations may be able tocall the main station when they desire. Such systems. have been devisedutilizing a separate wire other than the printer'signalling line forconducting the'call and selective operations. Howevenin the interest ofsimplicity it is desirable that the selection and calls may be made overthe'same line that carries the usual communication. r

In accordance with my invention I provide a communication circuit suchas a printing telegraph circuit of the general type described above,having a simplified selecting, calling and recording arrangementutilizing the common communicationlin'e.

- 'It is an object of ,myinventiorr to provide a selecting means undercontrol of a main station for making operative the printingtelegraphapparatus at another station.

' Another object of my invention is to provide a simple, inexpensiveselecting device and one a I which may be operated entirely byalternating current;

Another object of my invention is to maintain inoperative theprintingequipment at all stations except the one selected by the controlling pstation.

A further object of my invention is to provide for recording calls fromany of the stations at themain controlling station.

A' still further object of provide an arrangement for storing a codesignal corresponding to a call signal when the circuit is in operativecondition for communication, and to make this storage means operative totransmit the call signal immediately the communication circuit. k

According to amain feature ofmy invention the main or controllingstation includes a message call circuit "register with an associatedoperating 'relay, a selector unit with its associated upon terminationof relays and an answering jack and signal jack arrangement with anassociated printer set. Each way-station includes a polar relay with aselector unit and associated alternating current relays, a codetransmitter for transmitting calls to the centralstation with associatedalternating my invention is to of plug J will complete battery throughthe winding of relay M, sleeve contacts of jack K, winding of relay L toground.

the energizationof tery through contacts current relays and a standardprinter; set.

* Further objects and features of my invention will 'becomeapparent fromtheparticular description'of my invention made in connection with theaccompanying drawings, in which Figs. 1 and 1A taken together show acircuit diagram of an arrangement in accordance with my'invention, and

- Fig. '2 is a diagram indicating the line signals for selecting andcalling. v

In Fig. 1-is shown a control; station l0, comprising a printer set N, adrop jack unit l2, and a main oflice selector connected over a line to aplurality: of way-stations 40, 60, and 80, Fig. 1A, the line-beinggrounded at 9!]. The wiring at station 40 only. has been illustrated, itbeing understood that stations and have substantially similarcircuits. IY V In the normal idle conditionpositive battery extendsthrough windingof drop relay A, break and armature contactsot relay B, winding of relayC, breakand armature contacts of relay D toline 30. "At each station theline 30 extends through the-winding-of a polar relay E, armature andbackcontacts of relay F, break and armature contacts of 'relay G, and at thelast station 80 to ground at 90. Polar relays E will operate whenevernegative battery is appliedto the line from the control station l0.

p Method of selecting a station desired to select a particular H of arotary selector switch Whenever it is station, the rotor 2| is turned toengage one of its contacts I to gage its contact 3, which contactcorresponds to connected to main printthe jack K, The sleeve a circuitfrom negative way-station 40. Plug J er I l is then inserted into RelayL operates closing its contacts and causing the printer motor I3 over anobvious circuit and also connecting positive bat- M of theprinter tothetip of' plug J which, since it is inserted in jack K, extends positivebattery through the makediately and insure that the motor will rotatefor one complete revolution of cams P and Q and the brush R. As soon ascam Q has rotated a short distance its contacts will close operatingrelay B over an obvious circuit, transferring the line from the break tothe make contact ofthis relay, and negative battery will be applied toline 30 from negative source over contacts 3, 4 of relay M, and a makecontact of relay B.

Relay B will be released immediately after cam Q is rotated past thesmall depression provided therein. This operation and release of relay Bcauses operation of polar relay E at each Way station. The shortnegative impulse produced by operation of relay B is represented by thestart impulse 200 shown in Fig. 2. Relay E operates closing contacts Iand 4, completing an obvious circuit to an alternating current sourcecausing motor U to operate, rotating cams T and V with it. Contacts Iand 2 on cam T will close almost immediately and insure that the motor Uwill run one complete revolution of cams T and V. The guard lamp X willalso light at this time and serves as an indication that the line isbusy. Contacts 3 and 4 of cam T also close causing operation of relay S.

As motor N at the selecting station continues to rotate the brush R willpass over commutator segments I to II, inclusive, in succession. Assegment 3 is reached a circuit will be established from ground, brush R,segment 3, rotor H, winding of relay B to positive battery, operatingrelay B. Relay B will release as the brush R leaves segment 3. Thissends out on line 30 another negative impulse, selecting impulse 20I,Fig. 2, which is shorter than the start impulse 200, this short impulseof negative current transmitted over line 30 reoperates relay E. As camV has been rotating during this period, the indent 4| on its peripherywill permit its contacts to close momentarily at this point in itsrevolution. At the selected station, in this instance station 40, thiswill occur at the time when the selecting impulses cause relay E toclose its contacts. At the other stations the cams V are arranged sothat their notches are in different positions so that the contacts willnot be closed at any except the selected station. Alternating currentrelay G will operate from an A. C. source, winding of relay G, contactsof cam V, upper make contact of relay S, make contact of relay E toground, and will lock up through its own make contacts and contacts 3, 4to cam T. The other make contacts of relay G will extend power to themotor receptacle 43 over an obvious circuit for operation of theway-station printer motor, and the lower break contact of relay G opens,

removing the short circuit from the printer magnets 44 at theway-station.

Just before the end of the revolution of motor N at the selectingstation, brush R will pass over segment II causing energization of relayD from ground, brush R, contact II, winding of relay D, upper makecontact of relay M to posi tive battery. Relay D will operate and lockup through contacts I and 8. The line is transferred from contact 3 tocontact 6 of relay D, the tip of jack K, plug J to the main ofliceprinter set. Contacts I and 2 of relay D, hold relay C in its operatedposition, contacts 9 and I 0 of relay D open. Almost immediately afterthis operation of relay D, contacts of cam P Will open thereby breakingthe circuit for motor N causing it to stop. At this same time contacts Iand 3 of relay E and the contacts of relay S have completed a lockingcircuit for relay S which will remain operated. The contacts of cam Twill also open causing synchronous motor U to stop. Intercommunicationmay now be carried on between the main station I 0 and waystation 40.Cam V is adjustable on the shaft of motor U so that it may be positionedproperly to close its contacts only when the selecting impulsecorresponding to the station, is transmitted by the control station. Asthe cams V at the various stations are positioned to correspond todifferent station numbers only one can be selected at a time by thecontrol station.

To terminate a connection, plug J is removed from jack K at the controlstation. As the plug is removed the inner spring contacts of jack Kclose. A moment later relays M and L deenergize. As relay M releases itscontacts 6 and 1 open the circuit of relay D. Relay D is a slow releaserelay and will remain operated a short period after the circuit to itswinding has been opened. During this interval a circuit is establishedfrom negative battery through contacts 4 and 5 of relay M, tip and innerspring of jack K, contacts 6 and 4 of relay D to line 36, sending a veryshort disconnect signal 202 of Fig. 2 to the line. Relay E is operated,opening contacts I and 3 of relay E and deenergizing relays S and G.Relay D then releases, restoring positive battery to the line at itsupper break contacts and reestablishing the line circuit to its idlecondition. This negative impulse 202 is shorter than the start or selectimpulses and does not maintain relay E operated long enough for motor Uto start after relay S has released.

To call from a way-station Should a way-station desire to initiate acall, the operator thereat may operate the code transmitter provided ateach station. The code transmitter is provided with a code wheel Zarranged to send several short impulses tothe line and. then a longimpulse. The code wheel is adjustable on its motor shaft so that anypredetermined number of short impulses may be transmitted to the linepreceding the long impulse. For example, station 40 may cause theregister to record 2- short impulses, 205, 206 and one long impulse 201,Fig. 2. Stations 60 and may have three short impulses followed by a longimpulse and four short impulses followed by a long impulse,respectively. For the purposes of explanation, we will assume thatway-station 40 is calling. The operator there presses the call key 45,assuming that at this time the line is in its idle condition.Alternating current relay F will operate from A. C. source to groundover key 45 opening its upper contacts and will lock up through its owncontacts and contacts 5 and 6 of cam Y of the code transmitter. Theclosure of the lower outer make contacts of relay F completes an obviouscircuit to an alternating current source causing synchronous motor 46 ofthe code transmitter to rotate. Cams Z and Y rotate with'the motor.

distinctly understood that this illustration wa's Contacts 3 and 4 ofcam Y almost immediately close and insure rotation of the cams for onecomplete revolution. As the motor continues to rotate, contacts I and 2of cam Z cause interruptions in the line circuit. These interruptionsare a series of short'imp'ulses followed by a longer impulse caused bythe projections on cam Z. Upon transmission over the line'these impulseswill times and recorder 25 will record the call over a circuit extendingfrom positive battery, contacts 5, 6 of relay M, contacts of relay C,winding of relay 22, to ground. The number of short signals preceded bythe long signal determines which of the stations has called. The firstinterruption again operate and look through its o-wn'contacts andcontacts 5, E of cam Y. Closure of theouter make contacts of relay Fprepares a circuit from an alternating current source through the motor46 of the code transmitter. However, the circuit cannot be completed atthis time due tothe fact that the circuit is open at the lower makeconacts of relay S. Relay S will be locked up at this time and the codetransmitter cannot yet start. The moment the line circuit becomes idleby the removal of plug J at the main station, relay S will deenergize.This completes a circuit through the break contacts of relay S andcontacts 3, l of relay E, causing synchronous motor and the codetransmitter to rotate. The succeeding operations of recording the callare then the same as previously described.

If more than one way-station initiates a call when the line circuit isin the busy condition, relays F at each of these stations will lock upand prepare the circuits as previously described. As soon as the circuitbecomes idle, the code transmitters at all such stations will becomeoperative and will simultaneously transmit their code impulses to theline. Since mitters operate synchronously the record on the tape willindicate by the number and position of the long impulses, the number ofeach of the stations which is called. As an illustration, if stations 60and 80 having their code signals when made operative would causeregister 25 to record three short dashes followed by two long dashesindicating that both stations 4 and 5 had called. The operator then atthe main selecting stat-ion could set rotor H to one of these stationsanswering. the call and when that call was terminated, set the rotor tothe other station to complete a call there.

By use of this arrangement, it is seen that a simple operating printingtelegraph system is provided, wherein calls from the way-stations may beinitiated during periods when the line is busy and will be answered fromthe main station as soon as the busy condition of the line isterminated. Furthermore, a simple selective means utilizing merely thetime adjusting of the cams is provided so that complicated code signalcontrols are entirely avoided.

While I have disclosed by way of single embodiment of my invention,

illustration a it should be cause relay C to operate a like number of'all of these code transthe codes previously set V forth had initiated acallduring a busy period stations, printing telegraph Til ' tively,means responsive and synchronous mademerely by way of example and not asalimitation of the scope thereof. Various'adaptations, modifications andapplicationsof my invention may be made within the spirit and scope ofthis disclosure, as defined in the accompanying What is claimed is: 1

1. A communication system comprisinga main control station, adjustableway-station selective means at said control station, a plurality'ofwayapparatus and selective call receivers at each of said way-stations,a communication line interconnecting said main station and "saidway-stations, means at said main station for transmitting a startsignalsaid main station and to said start signal for way-stationselective call receivers respecto operation of said station selectivemeans for transmitting over said line a selecting signal dependent uponthe ad'- justment of said means, and means at the selected way-stationcontrolled by said-selective signal and said selectivecall receiver 'forrender ing the associated printing telegraph apparatus operative forcommunication over said line.

over said line, means at Way-stations responsive starting operation ofsaid means and said selective v2. A communication system according toclaim for transmitting said 1', wherein said means v start signaltransmits a signal of longer duration than said select signal. 1 1

3. A communication telegraph system accord-Q ing' to claim 1, furthercomprising synchronous ly operating motor means for operating saidway-station selective means and said selective call receivers, and meansoperative after one cycle of operation of said motors for stopping them.

4. A communication system comprising a main control station, printingtelegraph apparatus thereat, adjustable way station selective meansat-said control station, comprising an adjustable selecting switch, arotary selective transmitter operatively associated with said selectingswitch,

drive means for said transmitter, a plurality of way-stations, printingtelegraph apparatus and selective call receivers at each of saidway-stations, comprising synchronously operating drive means, andselective cam means driven by said synchronously operating drive means,a communication line interconnecting said main station and saidway-stations, means at said main station and way-stations responsive tosaid start signal for starting operation of said synchronous drivemeans, means responsive to operation of said rotary selectivetransmitter for transmitting over said line a selecting signal dependentupon the adjustment of said switch, and means at the selected waystationcontrolled by said selective signal and said selective cam means forrendering the associated printing telegraph apparatus operative forcommunication over said line.

5. A communication system according to claim 1, further comprising meansat each station for transmitting over said line call signals, means atsaid control station responsive to said call signals .for recording saidcalls, means at said way-stations for storingcalls in event said line isconnected for communication, and means responsive to disconnection ofsaid line after termination of communication for transmitting saidstored signals over said line to said means forrecording said calls.

6. A communication system comprising a main claims:-

station, a plurality of way-stations, a transmission'lineinterconnecting said main station and said way-stations, means forselectively establishing communication between said main station and aselected one of said way-stations, call transmitting means ateachway-station for transmitting calls over said line to said mainstation, recording means at said main station for recording said calls,signal storage means at each way-station for storing call signals whensaid line is being used for communication, and means responsive todisconnection of said line from communication condition for successivelytransmitting said call signals over said line to said recorder.

7. A communication system comprising a control station, printingtelegraph apparatus, a call recorder and an adjustable way-stationselective means at said control station; a plurality of waystations;printing telegraph apparatus, a selective call receiver, and. a controlstation calling means at each of said way-stations; a communication lineinterconnecting said control station and said way-stations; means atsaid control station for transmitting over said line start signals toinitiate operation of said selective call receivers at all of saidway-stations; means for transmitting over said line a station selectivesignal dependent upon the adjustment of said way-station selectivemeans; means at the waystation selected, responsive to said stationselective signal, for rendering the printing telegraph apparatus at theselected station operative; said control station call means comprisingcall transmitting means'for transmitting a distinctive signal from eachof said way-stations over said communication line to operate said callrecorder at said control station; means for initiating operation of saidcall transmitting means; said last named means preparing a circuit forinitiating said operation in event the line is in use for communication;and means responsive to termination of communication connections foroperating said transmitter,

8. A communication system comprising a main station, a plurality ofway-stations, a transmission line interconnecting said main station andsaid way-stations, call transmitting means at each way-station fortransmitting call signals over said line to said main station, means atsaid main station for. recording said calls, signal storage means ateach way-station for storing call signals and means responsive to achange in condition of said line for transmitting said call signals tosaid recorder.

9. A communication system according to claim 8, wherein said calltransmitting means comprises means for transmitting a plurality of shortimpulses followed by a long impulse, the number of short impulsespreceding the long impulse being different at each of said stations,whereby said signals Will be distinguishably recorded at said mainstation even when simultaneously transmitted.

FREDERICK G. HALLDEN.

